In the past various types of pneumatic hammers have been used in industry which provide a reciprocatory driving action for tools such as hammers, chisels, cutters, coarse punches and the like. Such tools are conventionally operated by pressing the tool held at the muzzle end of the hammer against a work piece. This action presents a rear driving or anvil end of the tool to engagement by a reciprocal driving member or internal hammer of the hammer to move the tool forward for the desired hammering, chiseling or coarse punching operation.
The punching of holes of varying size and preciseness of size with which this invention is concerned has presented a problem. The reciprocating coarse punches of the past have been of no use in punching consistent size holes for example in light sheet metal. Hand held punches or awls struck by a hammer are customarily employed which are tedious and time consuming, accident prone and require considerable energy and caution.